Net zero CO₂
A state in which human-caused CO₂ emissions are balanced by human-caused removals over a specified period.
Example
At a global level, sustained net zero CO₂ is central to stopping further CO₂-driven warming.
The catch
It differs from net zero across all greenhouse gases.
In more depth
Net zero CO₂, explained.
Net zero CO₂ marks the point at which human activity stops adding to the stock of CO₂ in the atmosphere, and it matters because warming from CO₂ tracks the cumulative total. That relationship lets scientists express a temperature limit as a carbon budget. Each year of delay before the balance is reached spends more of that budget.
The removals on the balance sheet must be human-caused. Carbon absorbed by the ocean, or by undisturbed forests responding to higher CO₂, does not count, which helps explain why national land-use figures and scientific estimates sometimes disagree. Other gases keep their own warming effect. A target labelled net zero CO₂ can leave them unaddressed. Compare it with any separate target for net zero greenhouse gases before judging ambition.